Carbonylation of olefin-diolefin mixtures



CARBONYLATION F OLEFIN-DIOLEFIN MIXTURES Philip Geoffrey Harvey andArthur William Charles Taylor, Norton-on-Tees, England, assignors toImperial Chemical Industries Limited, London, England, a corporation ofGreat Britain No Drawing. Application November 28, 1951, Serial No.258,752 Claims priority, application Great Britain September 12, 1949 6vClaims. (Cl. 260-604) This invention relates to the production ofoxygencontaining organic compounds and is a continuation-in part ofapplication Serial No. 180,705, filed August 21, 1950, now abandoned.

It has previously been common practice in the carbonylation of olefinesto employ as carbonylating gas a mixture of carbon monoxide and hydrogenin which the molar ratio COzHz was 1:1 since this gives thestoichiometric proportions for direct addition to the double bond, butgas of this composition has a strongly corrosive effect on ordinarysteel equipment. When the attempt is made to carbonylate alkenescontaining also diand/or polyenes using less corrosive gas mixtures anda dissolved cobalt compound as catalyst, it has now been found thatcarbonylation is inhibited, apparently owing to the presence of theselast two classes of compounds. However, it has been found possibleaccording to the present invention by having present initially an inertmedium, and using gas mixtures having compositions, and concentrationsof dissolved cobalt compounds, both as hereinafter defined, tocarbonylate these mixtures.

Moreover, the process of the present invention is economic in the sensethat it gives high conversions and outputs from these startingmaterials, which are so difficult to carbonylate. An additionaladvantage of the in vention is that it permits the return of largequantities of hydrogen from the later carbonyl decomposition zone andfrom the hydrogenation step, to the carbonylation step and the use asfeed gas in the last mentioned step of water gas with a COzHz ratio of1:1. This affords considerable economy in the overall process.Furthermore, by using carbonylating gas having the low CO ratios claimedthe need for costly CO-resistant apparatus is dispensed with. Besides,to the best of available knowledge, no one has been successful incontinuously carbonylating olefines from cracked paraflins using the lowCO:H2 ratios de scribed in the present specification without priortreatment of the alkene mixture.

According to the present invention oxygen-containing organic compounds,especially aldehydes, are produced by carbonylating alkene mixturescontaining C4 and higher alkenes, especially alpha-alkenes, togetherwith diand/ or poly-enes, which may be alicyclic or aliphatic, in thefollowing manner: forming an active carbonylating catalyst in a liquidorganic medium substantially inert under the reaction conditions bypassing thereinto at superatmospheric pressure and elevated temperaturea mixture comprising CO and H2, in which the partial pressure of CO isat least 50 atmospheres and the molar ratio of COzHz is at least 125,preferably at least 1:3, in the presence as catalyst of at least 0.01%,preferably at least 0.1%, by Weight of cobalt, calculated as metal,dissolved in the liquid, and thereafter feeding to this prepared mixturewhile contained in the same or a different reactor a mixture of carbonmonoxide and hydrogen, in which the molar ratio COzHz is from 3:7 to 2:3together with the 2,752,396 Patented June 26, 1956 alkene feedcontaining diand/or poly-enes, and containing continuing to carbonylatethe mixture while maintaining the concentration of dissolved cobalt inthe carbonylation zone at at least 0.1% by weight of the liquid.

The use as catalyst of a soluble organic compound in solution affordsthe advantages that it permits very accurate continuous control ofcobalt concentration in the reaction space, which is extremely importantin a sensitive reaction like the Oxo-process, and that, in contrast tocatalyst suspension-s, the reaction mixture can be easily pumped anderosion of valves and choking of lines can be substantially eliminated.The inhibiting effect of diand/ or poly-enes is very marked when activecarbonylating catalyst is to be formed from: dissolved organic cobaltcompounds. Moreover, the ability to use with difiicult alkene mixturesof this sort the low' cobalt proportions specified, viz., 0.1%, resultsin considerable saving of this costly metal.

It is a further advantage of the present invention that it is possibleto operate throughout with a carbonylating gas mixture in which theCOzHz ratio does not exceed 2:3 and which, therefore, is less corrosiveto ordinary steel.

The process of the invention is specially applicable to mixturescontaining from C4 to C18 mono-defines, in particular those containingup to 12. carbon atoms. Such mixtures may contain cyclic mono-olefinesin appreciable amounts.

While the inventionis not to be considered as depending on anyparticular theory, it is believed that. diand polyenes, especially thosewhich are conjugated, inhibit the carbonylation.

Diand poly-enes are distinguished by having higher densities andrefractive indices than the corresponding mono-olefines, and theirpresence is indicated by refractive index measurement, infra redspectroscopy or density measurement.

The invention is of especial value for the carbonylation of alkenescontaining, for example, C6-C8 mono-olefines produced by thermalcracking of hydrocarbons, e. g., paraflin wax.

Generally suitable reaction conditions are 13'01:90 C. preferably15'0-175" C., and. 200 to 300 atmospheres gauge (preferably 250atmospheres) of mixed carbon monoxide and hydrogen.

Suitable inert media, non-injurious to the carbonylation process are forexample, saturated butene trimer, hydrogenated' alcohol product,high-boiling parafi'inic. hydrocarbons, e. g., C16 hydrocarbons, andhigh boiling residues comprising ethers andether alcohols Obtained fromthe hydrogenation product of the carbonylated material. While C4 and C5alkenes are liquid within partial ranges of the reaction conditions itis nevertheless desirable with them to introduce an inert medium as wellas the C4 and C5 alkene feed in order to permit liquid phase operationthroughout the whole range of reaction conditions.

Preferably the cobalt is introduced as a soluble salt of an organic aciddissolved in the liquid medium, e. g., cobalt naphthenate, acetate,laurate, hexahydrobenzoate or 3,5,5-trirnethyl hexoate. The desiredconcentration of cobalt may be maintained in the reaction zone by, forexample, dissolving the soluble cobalt compound in the alkene feed or aportion thereof, or by introducing it as a solution in an inert mediumnon-injurious to the carbonylation reaction.

Saturated aldehydes produced by the process of the invention can bereadily hydrogenated to the corresponding alcohol, using for example, acopper or nickel catalyst and pressures of about 250 atmospheres gauge.Copper-on-zinc oxide and copper-on-chromia are especially suitable forthe hydrogenation step.

The invention is illustrated by the following example.

hols from normal heptene and octene.

Example (i) Operating according to the prior art process puredi-isobutene containing 0.1% of cobalt as naphthenate was fed to areaction zone at 155 C. and 250 atmospheres pressure together with amixture of carbon monoxide and hydrogen in which the mole ratio carbonmonoxide monoxide: hydrogen was 1:3 in the proportion of 1000 cubicmetres of free gas per cubic metre of diisobutene, the liquid spacevelocity being 0.5 litre per litre of free reaction space per hour.Carbonylation was initiated immediately and there were obtainedoxygenated organic compounds containing 3,5,5-trimethylhexanal. When theinlet gas was cut 013? the reaction ceased, but re-started immediatelyon reintroduction of the carbonylating gas.

(ii) The process was repeated under the same conditions as given inparagraph (i) except that the di-isobutene feed was replaced bydiisobutene containing 5% of cyclopentadiene. After passing the samecarbonylating gas for 2 hours it was found that no carbonylation hadoccurred.

(iii) Operation according to the process of the present invention willnow be described using an alkene feed which trial showed could not becarbonylated under the conditions described in paragraphs (i) and (ii)above.

A reactor is filled initially with a saturated C7 to C9 aliphaticmono-alcohol mixture containing 0.1% by weight cobalt as naphthenate andtreated at a gas rate of 500 cubic metres per cubic metre of emptyreaction space per hour with a mixed gas consisting of 25% CO and 75% H2at a pressure of 250 atmospheres gauge and temperature of 150 to 160 C.,for a period of at least 30 minutes. The liquid alkene feed, comprisingsubstantially C6 to C8 alpha monoolefines obtained by the thermalcracking of paraffin wax, containing 0.1% by Weight of dissolved cobaltas naphthenate is then injected continuously to the reactor at a liquidspace velocity of 0.5 litre/ litre/hour with a simultaneous mixed gasfeed containing 30% CO to give a gaszliquid feed volume rate of 1000cubic metres/cubic metre at a temperature of 150 to 175 C. and the abovepressure, when a pass conversion to oxygenated compounds of about 80% isobtained.

Operating according to the process of the invention the main endproducts obtained, after hydrogenation of the carbonylation product,from Ch normal olefines are the normal Cn+l alcohol and the 2-methyl-Cnalcohol (where n=the number of carbon atoms). Thus normal heptanol and2-methyl hexanol are obtained from normal hexene, and the correspondingnormal and Z-methyl alco- Other isomeric alcohols are also produced inminor amounts.

I claim:

1. A continuous process for the production of aldehydes by carbonylatingan olefine mixture produced by the cracking of hydrocarbons andcontaining alkenes having at least four carbon atoms in the molecule anda minor amount of at least one olefine selected from the groupconsisting of aliphatic and alicyclic diand polyenes which comprisesinitially preforming a large bulk of a solution of cobalt carbonylcatalyst in an inert organic medium by treating therein a solution of adissolved organic compound of cobalt in a concentration equivalent to atleast 0.01% of cobalt metal under superatmospheric temperature andpressure with a carbon monoxide/hydro gen gas mixture having a COzHzmolar ratio of at least 1:5 and having a carbon monoxide partialpressure of at least atmospheres and thereafter introducing andcontinuously feeding to said initially formed bulk of cobalt carbonylsolution said olefine mixture at to C. and at 200 to 300 atmospheres,while maintaining the concentration of cobalt at small concentration ofnot less than 0.1% of cobalt metal by weight of the said olefine mixtureby introducing a soluble organic compound of cobalt in solution and acarbon monoxide/hydrogen gas mixture in which the molar ratio of COzHzis from 3:7 to 2:3.

2. A process as claimed in claim 1 in which the said alkene containsfrom 4 to 12 carbon atoms in the molecule.

3. A process as claimed in claim 1 in which the molar ratio CO:H2 of thegas used to form said catalyst in the inert solvent does not exceed 2:3.

4. A process as claimed in claim 1 in which the alkene mixture comprisesC6-C8 mono-olefines obtained by the thermal cracking of higherhydrocarbons.

5. A process as claimed in claim 1 wherein the cobalt concentration inthe formation of said catalyst is at least 0.1% by weight.

6. A process as claimed in claim 1, in which conjugated diand poly-enesare present in the alkene mixture.

References Cited in the file of this patent UNITED STATES PATENTS2,437,600 Gresham et al Mar. 9, 1948 2,473,993 Gresham et al. June 21,1949 2,477,554 McKeever July 26, 1949 2,497,303 Gresham et al. Feb. 14,1950 2,530,989 Parker Nov. 21, 1950 2,587,858 Keulemans Mar. 4, 19522,647,149 Condit et al. July 28, 1953 OTHER REFERENCES Wender et al.:Critical Review of Chemistry of Oxo Synthesis, Bureau of Mines Report R.I. 4270, June 1948, pgs. 4, 5, 6.

1. A CONTINUOUS PROCESS FOR THE PRODUCTION OF ALDEHYDES BY CARBONYLATINGAN OLEFINE MIXTURE PRODUCED BY THE CRACKING OF HYDROCARBONS ANDCONTAINING ALKENES HAVING AT LEAST FOUR CARBON ATOMS IN THE MOLECULE ANDA MINOR AMOUNT OF AT LEAST ONE OLEFINE SELECTED FROM THE GROUPCONSISTING OF ALIPHATIC AND ALICYCLIC DI- AND POLYENES WHICH COMPRISESINITIALLY PERFORMING A LARGE BULK OF A SOLUTION OF COBALT CARBONYLCATALYST IN AN INERT ORGANIC MEDIUM BY TREATING THEREIN A SOLUTION OF ADISSOLVED ORGANIC COMPOUND OF COBALT IN A CONCENTRATION EQUIVALENT TO ATLEAST 0.01% OF COBALT METAL UNDER SUPERATMOSPHERIC TEMPERATURE ANDPRESSURE WITH A CARBON MONOXIDE/HYDROGEN GAS MIXTURE HAVING A CO:H2MOLAR RATIO OF AT LEAST 1:5 AND HAVING A CARBON MONOXIDE PARTIALPRESSURE OF AT LEAST 50 ATMOSPHERES AND THEREAFTER INTRODUCING ANDCONTINUOUSLY FEEDING TO SAID INITIALLY FORMED BULK OF COBALT CARBONYLSOLUTION SAID OLEFINE MIXTURE AT 130* TO 190* C. AND AT 200 TO 300ATMOSPHERES, WHILE MAINTAINING THE CONCENTRATION OF COBALT AT SMALLCONCENTRATION OF NOT LESS THAN 0.1% OF COBALT METAL BY WEIGHT OF THESAID OLEFIN MIXTURE BY INTRODUCING A SOLUBLE ORGANIC COMPOUND OF COBALTIN SOLUTION AND A CARBON MONOXIDE/HYDROGEN GAS MIXTURE IN WHICH THEMOLAR RATIO OF CO:H2 IS FROM 3:7 TO 2:3.